Chapter 1

Introduction to Networks and
Networking Concepts

What is Networking?

• Connecting computers to form a Local Area Network (LAN)
• Sharing
  • Hardware
  • Software
  • Information

Networking Fundamentals

• Quickly & efficiently share:
  • Data
    • Exchange Information
    • Route data from user to user
    • Use E-mail to communicate
  • Peripherals
    • Printers
    • Scanners
    • Fax
• sharing saves $

Standalone Computer

A Simple Network

Local & Wide Area Networks

• Early networks were custom built
• Connecting a dozen computers
• Only 1 or 2 peripherals
• Early Ethernet
  • 30 users
  • Total span of 601 feet
• Local Area Network (LAN)
  • A single collection of machines & peripherals
  • Less than 100 computers
  • Distance spanned less than 1000 feet
  • Basic building block for larger networks-Internetworks
• Internetworks
  • A network of networks
  • A networked collection of LANs
  • More than one floor in a business
  • Multiple buildings
  • Campus environment
• Wide Area Networks (WAN)
  • Spans miles of distance
  • Two or more separate locations
  • Down the road or across the world
  • Microsoft, Federal Express
• Metropolitan Area Network (MAN)
  • WAN technology to connect LANs
  • Within a geographical region
  • Municipality or communications carrier
  • LAN, WAN, MAN technology
• The Internet
  • A WAN internetwork
  • Millions of machines worldwide
  • The World Wide Web (WWW)

Networking Terminology

• Client Server Networks
  • Client/Server relationship
    • Client requests shared resources
    • Server responds & shares resources
  • Concentrate CPU power & storage capacity
  • Windows NT Server
• Peer to Peer
  • Client/Server role interchanges
  • Windows 95
  • Windows for Workgroups

Network Medium (media)

• Carries network messages
• Connects machines together on network
• Three types:
  • Metallic cable
    • Twisted pair
    • Coaxial
  • Fiber optic cable
  • Wireless

Network Interface Card (NIC)

• Physical link between machine & network
• Connection between machine & medium
• Also known as network adapter

Network Protocols

• Common set of communication rules
• Identify 'oneself" & others on network
• Interpret signals
• Begin & end network communication
• Manage network information exchange
• Protocol Examples
  • TCP/IP (for the Internet)
  • IPX/SPX & NWLINK (for Novell)
  • NetBEUI (for Microsoft)

Network Software

• Programs that access the network
• Network Operating System (NOS)
  • Windows NT
  • Novell NetWare (IntranetWare)
• Consist of client & server components

Network Layers

• Network Applications (NOS & client)
• Instruct network medium
• Using machines interface (NIC)
• Address & exchange information
• To other machines on LAN or WAN

Network Types

• Peer to Peer
  • Windows 95
  • Windows for Workgroups
• Client Server (server-based)
  • Windows NT
  • Novell

Peer to Peer

• No centralized control
• Act as both client & server
• User controls access to machine
• Institutionalized chaos & security concerns
• Adding machines slows network down
• Peer to Peer Advantages
  • Easy to install & configure
  • Users control individual shared resources
  • Inexpensive to purchase & operate
  • No Network Administrator
  • Best for 10 or fewer users
• Peer to Peer Disadvantages
  • Security for only a single resource at a time
  • Users may need to know many passwords
  • Individual machine backups
  • Speed decreases while sharing
  • No central location/access of data

Server Based Networks

• Server is the key to this type
• Centralized control of resources
• Utilize faster processors
• More memory
• Extra peripherals
• Server Security
  • Physical access to the server
  • Specialized sentry servers
  • Domain model
  • Account names
  • Passwords
• Server Based Advantages
  • Central security/ accounts/ access
  • Simplify network administration
  • Powerful/ efficient access to resources
  • Single password for each user
  • Best for high use, user, networks
• Server Based Disadvantages
  • Server failure results in unusable network
  • Server failure results in loss of resources
  • Expert staff to manage increases cost
  • Dedicated hardware increases cost
  • Dedicated software increases cost

Hybrid Networks

• Combination networks
• Windows for Workgroups
• Windows 95
• Windows NT Server
• Windows NT Workstation

Server Hardware Requirements

Specialized Servers

• Application Servers
  • Server side of Client/Server applications
  • Supply application services and data
  • Provide processing services
  • Microsoft SQL Server
    • runs on Windows NT Server
• Communication Servers
  • Access beyond networks local scope
  • Inbound & outbound resource access
  • Dial in via modem
  • Windows NT server Remote Access Server
  • (RAS) manages dial in network connections
• Domain Controllers/Directory Servers
  • Locate, store, & secure information about network
  • Allows computers, users, groups, & resources to be combined into domains
  • Domain access allows single login to all allowed resources
• Fax Servers
  • Manage network fax traffic
  • Receive incoming telephone faxes
  • Distribute to network users
  • Collect outgoing network faxes
  • Send outgoing telephone faxes
• File and Print Servers
  • File storage & File retrieval
  • Access to network printers
  • Applications run locally
  • Store data on server
  • Window NT server is capable
• Mail Servers
  • E-mail for network users
  • Allow local exchange of messages
  • Permit server based storage of messages
  • Forward user messages to destination
  • Microsoft Exchange Server
• Web Servers
  • World Wide Web (WWW)
  • File Transfer Protocol (FTP)
  • Gopher services
  • Intranets
  • NT Server Internet Information Server (IIS)

Selecting the Right Network

• Budget considerations; number of users?
• Physical span of the network?
• Specialized servers; services desired?
• Internetwork or WAN access?
• Future growth?